The present invention relates to an engine in which an auxiliary can easily be supported axially outside a flywheel mounted at an end of a crankshaft.
In general, an engine block forming a body of an engine is bisected into a cylinder block and a crankcase on a parting plane including an axis of a crankshaft. The crankshaft is supported so as to be sandwiched between the cylinder block and the crankcase.
In addition, in a single-cylinder vertical engine described in Japanese Patent Application Laid-open No. 4-362231, an engine body is comprised of an engine block integrally provided with a cylinder bore and a crankcase, and an upper cover closing an opening in an upper surface of the engine block. A lower journal of the crankshaft is supported in a bearing bore provided in the engine block, and an upper journal of the crankshaft is supported in a bearing bore provided in the upper cover.
In the former engine (the engine having the parting plane including the axis of the crankshaft), when a flywheel is mounted at an end of the crankshaft and further, an auxiliary such as a recoil starter is disposed axially outside the crankshaft, it is necessary to commonly work the cylinder block and the crankcase as a coupled member, and moreover, a part such as a mounting bracket is specially required to prevent an axis of the auxiliary and an axis of the crankshaft from being deviated from each other, resulting in increases in number of parts and number of assembling steps.
Further, in the latter engine (the engine including the cover member having the bearing bore defined in one end, and the engine block having the bearing bore defined in the other end), a mounting support portion is formed to extend from the side of an auxiliary beyond the flywheel toward the cover member coupled into a large opening in the engine block. As a result, the size of the cover member cannot be reduced to a level smaller than an area defined by a coupled portion of the auxiliary, and the opening in the engine block is also increased in size. This is a factor of hindrance of reductions in size and weight of the engine.
The present invention has been accomplished with the above circumstances in view, and it is an object of the present invention to ensure that the auxiliary can easily and reliably be supported axially outside the flywheel mounted on the crankshaft.
To achieve the above object, according to the present invention, there is proposed an engine comprising a crankshaft having a flywheel at one end thereof, an engine block including a cylinder bore and a crankcase and supporting a journal at the other end of the crankshaft, and a cover member coupled to the engine block to close an opening in the engine block and supporting a journal at the one end of the crankshaft, characterized in that the cover member has auxiliary-supporting portions integrally formed thereon to extend radially outwards beyond an outer periphery of the flywheel, and an auxiliary located axially outside the flywheel is supported on the auxiliary-supporting portions.
With the above arrangement, the auxiliary-supporting portions are integrally formed on the cover member closing the opening in the engine block to extend radially outwards beyond the outer periphery of the flywheel mounted to the crankshaft supported at one end thereof on the cover member, and the auxiliary located axially outside the flywheel is supported on the auxiliary-supporting portions. Therefore, the auxiliary can be supported easily and reliably without provision of a special mounting bracket and a stay, while preventing the interference with the flywheel. A coupled portion of the cover member in the opening in the engine block is not influenced or less influenced by the disposition of a mounting portion of the auxiliary. As a result, the opening in the engine block can be reduced in size to reduce the size and weight of the engine block.
In addition to the above arrangement, there is proposed an engine, wherein the auxiliary is a recoil starter coaxially connected to the one end of the crankshaft.
With such arrangement, the recoil starter is supported on the auxiliary-supporting portions integrally formed on the cover member supporting the one end of the crankshaft and hence, the recoil starter can be disposed precisely on an axis of the crankshaft.
Meanwhile, a rotor 78 in an embodiment corresponds to the flywheel in the present invention; recoil starter-supporting arms 712, 713, 713 in the embodiment correspond to the auxiliary-supporting portions in the present invention; and a recoil starter 18 in the embodiment corresponds to the auxiliary in the present invention.
In addition to the above arrangement, there is proposed an engine, wherein the engine block has an assembling bore for assembling a larger end of a connecting rod at a location opposed to the cylinder bore.
With the above arrangement, an operation for assembling the larger end of the connecting rod can be conducted through the assembling bore defined in the engine block. Therefore, it is unnecessary to enlarge the opening in the engine block in order to conduct the assembling operation, thereby contributing to a reduction in size of the engine block.